Sunlight, in the broad sense,'s the total spectrum of the electromagnetic radiation given off by the Sun. On Earth, sunlight's filtered through the atmosphere, and the solar radiation's obvious as daylight when the Sun's above the horizon. Near the poles in summer, the days are longer and the nights are shorter or non-existent. In the winter at the poles the nights are longer and for some periods of time, sunlight may not occur at all. When the direct radiation isn't blocked by clouds, it's exp… (More on Sunlight)